A discharge lamp, such as a high pressure mercury-vapor lamp or a metal halide lamp, is used as the light source of a projector. Optimum drive conditions (the current value, frequency, and waveform of a drive current) of a discharge lamp differ depending on the condition of the discharge lamp. For example, the optimum drive conditions differ between a point immediately after a lighting starts and after a certain amount of time has elapsed from the lighting, and the optimum drive conditions also differ between a discharge lamp used for a short period and a discharge lamp close to its lifetime limit. Also, the optimum drive conditions differ depending on the type of a discharge lamp.
The use of a discharge lamp under non-optimum drive conditions causes a discharge tube to be blackened or devitrified. Also, it causes an occurrence of a flicker too, for example, in the event of using the discharge lamp in a projector, the brightness of a projected video fluctuates during the use of the projector.
For this reason, for example, in JP-T-2002-533884, a discharge lamp lighting device is proposed wherein, a control circuit in which a plurality of drive conditions are preset being provided inside the discharge lamp lighting device, it is possible to appropriately select a drive condition in accordance with the condition of a discharge lamp.